This invention relates to novel silyl esters of N-phosphonomethylglycine as well as to their use as post-emergence herbicides, herbicidal compositions, and herbicidal methods.
N-phosphonomethylglycine has been discovered to be a particularly useful herbicide and the herbicidal method employing such compound is disclosed in U.S. Pat. No. 3,799,758. It is taught therein that N-phosphonomethylglycine, its salts, amides, esters, and other derivatives are highly desirable herbicides. Included within the esters of U.S. Pat. No. 3,799,758 are hydrocarbon and hydrocarbonoxy hydrocarbon esters having from 1 to 18 carbon atoms in the ester group and the halogenated hydrocarbon and hydrocarbonoxyhydrocarbon groups. However, the patent discloses only the diesters of N-phosphonomethylglycine.
The benzyl and aryl triesters of N-phosphonomethylglycine are disclosed in U.S. Pat. No. 4,120,689. The triesters and the hydrolysis products thereof containing at least one benzyloxy or aryloxy group are useful as post-emergence herbicides.
Japanese Patent Publication LOP No. 56520/1978 (published May 23, 1978) describes as an intermediate a trimethylsilyl ester of N-phosphonomethylglycinonitrile. This intermediate is easily hydrolyzed at room temperature by addition of a water/methanol mixture to give: ##STR1##